This invention generally relates to rotary filling machines, more particularly to an apparatus and method having various features for precisely controlling the fill level delivered to the containers being filled on a rotary head, including a sensor that is positioned from the central axis of the rotary head at a distance that is substantially the same as that between this central axis and each fill nozzle. Also included are control assemblies to maintain the desired level within the liquid reservoir and to adjust the fill time while the apparatus is in operation. Other features include improved explosion-proofing by protecting electronic components within air-purged environments, structural features for facilitating machine clean-up without dismantling same, more consistent liquid flow through the fill nozzles, and features for readily adjusting the height of the rotary head for accommodating various different sizes of containers to be filled.
Rotary fillers have been known for filling containers with a liquid product, including the filling of aerosol containers with liquid product to be packaged with a propellant. Representative of the general type of apparatus that is used for filling liquid components and products is that shown in U.S. Pat. No. Re. 23,830, wherein a rotating turntable having a plurality of operating stations receives a flow of containers which are filled with liquid while the containers move along the rotating turntable.
In these types of operations, it is typically very important to accurately and closely control the amount of liquid that is fed into each container. Such is important to avoid a shortfall of product filled into the container, to avoid product waste, and to insure that the proper amount of space is available for subsequent filling of the propellant thereinto when desired. One difficulty that has been encountered over the years in this regard is the fact that these rotary heads are rotating while the filling mechanism is in operation, which causes the development of forces such as centrifugal forces that affect the metering of liquids while they are passed through the rotary head. Particularly troublesome is the fact that these forces will vary with the speed at which the rotary head is operating, which typically will vary at differing points of the filling operation, for example, when the rotary head must be slowed or stopped in order to accommodate a subsequent operation. Most of these types of variations are not predictable, and it is difficult for an operator to anticipate when a fill level adjustment might be needed.
Another difficulty with these types of devices is attempting to adjust the fill level while the containers are traversing their path along the rotating turntable. Additionally, in certain instances, expensive and cumbersome explosion-proof cabinetry and components are incorporated as a safety measure, which may be important depending upon the contents being filled into the containers.
Often, with these types of rotary filling machines, particularly that portion of the machinery which adds the liquid component, it is necessary to clean out the various passageways through which the liquid product flows before changing over to a different liquid product. For example, when the liquid being filled is a paint, it is necessary to clean these passageways when changing from one color to another, even though the propellant subsequently added may be exactly the same for any such color. Typically, such a clean up operation involves disassembling at least a portion of the device in order to treat same with solvents and the like.
The present invention responds to these various needs and difficulties by various features which combine to provide a constant hydraulic head that is adjustable while the device is in operation, such including providing a sensor that is located substantially the same distance from the axial center of the rotary turntable as is the opening through which the liquid flows into each container that is being filled. An alignment and trough arrangement are also provided in association with a head raising and lowering assembly whereby cleaning of the liquid passageways can be carried out on a generally automatic basis. Suitable cabinetry and fluid flow mechanisms are provided in order to explosion-proof the device.
It is accordingly a general object of the present invention to provide an improved rotary filling device.
Another object of the present invention is to provide an improved rotary filling device having a substantially constant hydraulic head in order to minimize the effects of variations in centrifugal force on the liquid while the device is being operated.
Another object of this invention is to provide means for adjusting the fill size at any station of a rotary filling device while that device is in operation.
Another object of the present invention is to provide an improved rotary filling device which includes a sharp-edged orifice nozzle design for enhancing fill consistency.
Another object of the present invention is to provide an improved rotary filling device having a pneumatic nozzle actuation feature for more reliable nozzle opening and closing procedures.
Another object of the present invention is to provide an improved rotary filling device having clean-in-place capability that avoids the need to disassemble components in order to clean the liquid flow passageways thereof.
Another object of the present invention is to provide an improved rotary filling device having a simplified and easy-to-operate means for adjusting the gang head height.
Another object of the present invention is to provide an improved rotary filling device that utilizes air purging at air-electrical interfaces in order to eliminate the necessity for explosion-proof electrical wiring and components.